They're sucking a few pennies out of every transaction on these exchanges, the long-term effect is that of a parasite in a larger host. Sure they may have some small benefit of improving liquidity to the market, but overall they're causing harm by reducing the returns of legitimate traders.
If they're adding a lot of liquidity, I'm happy with them reducing my returns a little. If they add a little liquidity, I'm not happy with them reducing my returns a lot. There are questions to be answered that we can't get at from an armchair (at least, the metaphorical armchair).
I think we need the government to step in and slow down google. They return search results unfairly fast, it prevents underfunded companies from competing.
